Assessment of the comparative agreement between chest radiographs and CT scans in intensive care units.

PURPOSE: Chest radiographs in critically ill patients can be difficult to interpret due to technical and clinical factors. We sought to determine the agreement of chest radiographs and CT scans, and the inter-observer variation of chest radiograph interpretation, in intensive care units (ICUs). METHODS: Chest radiographs and corresponding thoracic computerised tomography (CT) scans (as reference standard) were collected from 45 ICU patients. All radiographs were analysed by 20 doctors (radiology consultants, radiology trainees, ICU consultants, ICU trainees) from 4 different centres, blinded to CT results. Specificity/sensitivity were determined for pleural effusion, lobar collapse and consolidation/atelectasis. Separately, Fleiss' kappa for multiple raters was used to determine inter-observer variation for chest radiographs. RESULTS: The median sensitivity and specificity of chest radiographs for detecting abnormalities seen on CTs scans were 43.2% and 85.9% respectively. Diagnostic sensitivity for pleural effusion was significantly higher among radiology consultants but no specialty/experience distinctions were observed for specificity. Median inter-observer kappa coefficient among assessors was 0.295 ("fair"). CONCLUSIONS: Chest radiographs commonly miss important radiological features in critically ill patients. Inter-observer agreement in chest radiograph interpretation is only "fair". Consultant radiologists are least likely to miss thoracic radiological abnormalities. The consequences of misdiagnosis by chest radiographs remain to be determined.

Tissue factor expression in monocyte subsets during human immunothrombosis, endotoxemia and sepsis.

INTRODUCTION: Tissue factor expression on monocytes is implicated in the pathophysiology of sepsis-induced coagulopathy. How tissue factor is expressed by monocyte subsets (classical, intermediate and non-classical) is unknown. METHODS: Monocytic tissue factor surface expression was investigated during three conditions. Primary human monocytes and microvascular endothelial cell co-cultures were used for in vitro studies. Volunteers received a bolus of lipopolysaccharide (2 ng/kg) to induce endotoxemia. Patients with sepsis, or controls with critical illness unrelated to sepsis, were recruited from four intensive care units. RESULTS: Contact with endothelium and stimulation with lipopolysaccharide reduced the proportion of intermediate monocytes. Lipopolysaccharide increased tissue factor surface expression on classical and non-classical monocytes. Endotoxemia induced profound, transient monocytopenia, along with activation of coagulation pathways. In the remaining circulating monocytes, tissue factor was up-regulated in intermediate monocytes, though approximately 60 % of individuals (responders) up-regulated tissue factor across all monocyte subsets. In critically ill patients, tissue factor expression on intermediate and non-classical monocytes was significantly higher in patients with established sepsis than among non-septic patients. Upon recovery of sepsis, expression of tissue factor increased significantly in classical monocytes. CONCLUSION: Tissue factor expression in monocyte subsets varies significantly during health, endotoxemia and sepsis.

Patient Self-Testing of Kidney Function at Home, a Prospective Clinical Feasibility Study in Kidney Transplant Recipients.

Introduction: People with long-term health conditions often attend clinics for kidney function tests. The Self-Testing Own Kidneys (STOK) study assessed feasibility of kidney transplant recipients using hand-held devices to self-test kidney function at home and investigated agreement between home self-test and standard clinic test results. Methods: A prospective, observational, single-center, clinical feasibility study (TRN: ISRCTN68116915), with N = 15 stable kidney transplant recipients, investigated blood potassium and creatinine results agreement between index self-tests at home (patient self-testing of capillary blood, using Abbott i-STAT Alinity analyzers [i-STAT]) and reference tests in clinic (staff sampled venous blood, analyzed with laboratory Siemens Advia Chemistry XPT analyzer) using Bland-Altman and error grid analysis. Results: The mean within-patient difference between index and reference test in creatinine was 2.25 µmol/l (95% confidence interval [CI]: -12.13, 16.81 µmol/l) and in potassium was 0.66 mmol/l (95% CI: -1.47, 2.79 mmol/l). All creatinine pairs and 27 of 40 (67.5%) potassium pairs were judged clinically equivalent. Planned follow-up analysis suggests that biochemical variables associated with potassium measurement in capillary blood were predominant sources of paired test result differences. Paired patient and nurse i-STAT capillary blood test potassium results were not statistically significantly different. Conclusions: This small feasibility study observed that training selected patients to competently use hand-held devices to self-test kidney function at home is possible. Self-test creatinine results showed good analytical and clinical agreement with standard clinic test results. Self-test potassium results showed poorer agreement with standard clinic test results; however, patient self-use of i-STATs at home was not a statistically significant source of difference between paired potassium test results.

Research Bronchoscopies in Critically Ill Research Participants: An Official American Thoracic Society Workshop Report.

Bronchoscopy for research purposes is a valuable tool to understand lung-specific biology in human participants. Despite published reports and active research protocols using this procedure in critically ill patients, no recent document encapsulates the important safety considerations and downstream applications of this procedure in this setting. The objectives were to identify safe practices for patient selection and protection of hospital staff, provide recommendations for sample procurement to standardize studies, and give guidance on sample preparation for novel research technologies. Seventeen international experts in the management of critically ill patients, bronchoscopy in clinical and research settings, and experience in patient-oriented clinical or translational research convened for a workshop. Review of relevant literature, expert presentations, and discussion generated the findings presented herein. The committee concludes that research bronchoscopy with bronchoalveolar lavage in critically ill patients on mechanical ventilation is valuable and safe in appropriately selected patients. This report includes recommendations on standardization of this procedure and prioritizes the reporting of sample management to produce more reproducible results between laboratories. This document serves as a resource to the community of researchers who endeavor to include bronchoscopy as part of their research protocols and highlights key considerations for the inclusion and safety of research participants.

Tracheostomy in children is associated with neutrophilic airway inflammation.

BACKGROUND: Tracheostomies in children are associated with significant morbidity, poor quality of life, excess healthcare costs and excess mortality. The underlying mechanisms facilitating adverse respiratory outcomes in tracheostomised children are poorly understood. We aimed to characterise airway host defence in tracheostomised children using serial molecular analyses. METHODS: Tracheal aspirates, tracheal cytology brushings and nasal swabs were prospectively collected from children with a tracheostomy and controls. Transcriptomic, proteomic and metabolomic methods were applied to characterise the impact of tracheostomy on host immune response and the airway microbiome. RESULTS: Children followed up serially from the time of tracheostomy up to 3 months postprocedure (n=9) were studied. A further cohort of children with a long-term tracheostomy were also enrolled (n=24). Controls (n=13) comprised children without a tracheostomy undergoing bronchoscopy. Long-term tracheostomy was associated with airway neutrophilic inflammation, superoxide production and evidence of proteolysis when compared with controls. Reduced airway microbial diversity was established pre-tracheostomy and sustained thereafter. CONCLUSIONS: Long-term childhood tracheostomy is associated with a inflammatory tracheal phenotype characterised by neutrophilic inflammation and the ongoing presence of potential respiratory pathogens. These findings suggest neutrophil recruitment and activation as potential exploratory targets in seeking to prevent recurrent airway complications in this vulnerable group of patients.

Providing care for children with tracheostomies: a qualitative interview study with parents and health professionals.

OBJECTIVES: To explore the experience of caring for children with tracheostomies from the perspectives of parents and health professional caregivers. DESIGN: Qualitative semistructured interview study. SETTING: One region in England covered by a tertiary care centre that includes urban and remote rural areas and has a high level of deprivation. PARTICIPANTS: A purposive sample of health professionals and parents who care for children who have, or have had, tracheostomies and who received care at the tertiary care centre. INTERVENTION: Interviews undertaken by telephone or video link. PRIMARY AND SECONDARY OUTCOME MEASURES: Qualitative reflexive thematic analysis with QSR Nvivo 12. RESULTS: This paper outlines key determinants and mediators of the experiences of caregiving and the impact on psychological and physical health and quality of life of parents and their families, confidence of healthcare providers and perceived quality of care. For parents, access to care packages and respite care at home as well as communication and relationships with healthcare providers are key mediators of their experience of caregiving, whereas for health professionals, an essential influence is multidisciplinary team working and support. We also highlight a range of challenges focused on the shared care space, including: a lack of standardisation in access to different support teams, care packages and respite care, irregular training and updates, and differences in health provider expertise and experiences across departments and shift patterns, exacerbated in some settings by limited contact with children with tracheostomies. CONCLUSIONS: Understanding the experiences of caregiving can help inform measures to support caregivers and improve quality standards. Our findings suggest there is a need to facilitate further standardisation of care and support available for parent caregivers and that this may be transferable to other regions. Potential solutions to be explored could include the development of a paediatric tracheostomy service specification, increasing use of paediatric tracheostomy specialist nurse roles, and addressing the emotional and psychological support needs of caregivers.

Nitration of chemokine CXCL8 acts as a natural mechanism to limit acute inflammation.

Chemokine CXCL8 is a key facilitator of the human host immune response, mediating neutrophil migration, and activation at the site of infection and injury. The oxidative burst is an important effector mechanism which leads to the generation of reactive nitrogen species (RNS), including peroxynitrite. The current study was performed to determine the potential for nitration to alter the biological properties of CXCL8 and its detection in human disease. Here, we show peroxynitrite nitrates CXCL8 and thereby regulates neutrophil migration and activation. The nitrated chemokine was unable to induce transendothelial neutrophil migration in vitro and failed to promote leukocyte recruitment in vivo. This reduced activity is due to impairment in both G protein-coupled receptor signaling and glycosaminoglycan binding. Using a novel antibody, nitrated CXCL8 was detected in bronchoalveolar lavage samples from patients with pneumonia. These findings were validated by mass spectrometry. Our results provide the first direct evidence of chemokine nitration in human pathophysiology and suggest a natural mechanism that limits acute inflammation.

Oropharyngeal swallowing physiology and safety in patients with Idiopathic Pulmonary Fibrosis: a consecutive descriptive case series.

INTRODUCTION: Dysphagia occurs in multiple respiratory pathophysiologies, increasing the risk of pulmonary complications secondary to aspiration. Reflux associated aspiration and a dysregulated lung microbiome is implicated in Idiopathic Pulmonary Fibrosis (IPF), but swallowing dysfunction has not been described. We aimed to explore oropharyngeal swallowing in IPF patients, without known swallowing dysfunction. METHODS: Fourteen consecutive outpatients with a secure diagnosis of IPF were recruited and the 10-item Eating Assessment Tool (Eat 10) used to assess patient perception of swallowing difficulty. Oropharyngeal swallowing was assessed in ten patients using Videofluoroscopy Swallow Studies (VFSS). The studies were rated using validated scales: Penetration-Aspiration Scale (PAS); standardised Modified Barium Swallow Impairment Profile (MBSImP). RESULTS: EAT-10 scores indicated frank swallowing difficulty in 4/14 patients. Videofluoroscopy Studies showed that 3/10 patients had airway penetration, and one aspirated liquid without a cough response. Median MBSImp for oral impairment was 5, range [3-7] and pharyngeal impairment 4, range [1-14] indicating, overall mild alteration to swallowing physiology. CONCLUSION: We conclude that people with IPF can show a range of swallowing dysfunction, including aspiration into an unprotected airway. To our knowledge, this is the first report on swallowing physiology and safety in IPF. We believe a proportion of this group may be at risk of aspiration. Further work is indicated to fully explore swallowing in this vulnerable group.

A Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Assay Identifies Nilotinib as an Inhibitor of Inflammation in Acute Myeloid Leukemia.

Inflammatory responses are important in cancer, particularly in the context of monocyte-rich aggressive myeloid neoplasm. We developed a label-free cellular phenotypic drug discovery assay to identify anti-inflammatory drugs in human monocytes derived from acute myeloid leukemia (AML), by tracking several features ionizing from only 2500 cells using matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry. A proof-of-concept screen showed that the BCR-ABL inhibitor nilotinib, but not the structurally similar imatinib, blocks inflammatory responses. In order to identify the cellular (off-)targets of nilotinib, we performed thermal proteome profiling (TPP). Unlike imatinib, nilotinib and other later-generation BCR-ABL inhibitors bind to p38α and inhibit the p38α-MK2/3 signaling axis, which suppressed pro-inflammatory cytokine expression, cell adhesion, and innate immunity markers in activated monocytes derived from AML. Thus, our study provides a tool for the discovery of new anti-inflammatory drugs, which could contribute to the treatment of inflammation in myeloid neoplasms and other diseases.

A human model of bilateral pulmonary vein sampling to assess the effects of one-lung ventilation on neutrophil function.

BACKGROUND: Neutrophil activation drives lung complications after cardiopulmonary bypass (CPB). Evidence suggests the healthy, ventilated lung may beneficially re-condition pro-inflammatory neutrophils. However, evidence in humans is lacking, due to a paucity of good models. CPB with simultaneous central venous and bilateral pulmonary vein sampling provides an opportunity to model effects of one-lung ventilation. The study's primary objectives were to establish a model of intra-operative, bilateral pulmonary vein sampling and to determine whether neutrophil function differed after passing through inflated or deflated lungs. METHODS: Seventeen patients having "on pump" coronary artery bypass grafting (CABG) with one-lung ventilation (in two cohorts with tidal volume 2ml kg-1 and FiO2 0.21, or tidal volume 4 ml kg-1 and FiO2 0.5 respectively) were recruited. Cohort 1 consisted of 9 patients (7 male, median age 62.0 years) and Cohort 2 consisted of 8 male patients (median age 65.5 years). Recruitment was via prospective screening of scheduled elective and non-elective CABG procedures with cardiopulmonary bypass. Each patient had five blood samples taken-central venous blood pre-operatively; central venous blood pre-CPB; central venous blood post-CPB; pulmonary venous blood draining the ventilated lung post-CPB; and pulmonary venous blood draining the deflated lung post-CPB. Neutrophil phagocytosis and priming status were quantified. Plasma cytokines were measured. RESULTS: Phagocytosis and priming were not significantly different in neutrophils returning from the ventilated lung as compared to the non-ventilated lung. Plasma IL-6, IL-8 and IL-10 were significantly elevated by CPB. CONCLUSIONS: The intra-operative, bilateral pulmonary vein sampling model provides unique opportunities to assess biological effects of interventions to one lung, with the other lung acting as an internal control. Single-lung ventilation during CPB had no significant effects on neutrophil function.

Hypoxia shapes the immune landscape in lung injury and promotes the persistence of inflammation.

Hypoxemia is a defining feature of acute respiratory distress syndrome (ARDS), an often-fatal complication of pulmonary or systemic inflammation, yet the resulting tissue hypoxia, and its impact on immune responses, is often neglected. In the present study, we have shown that ARDS patients were hypoxemic and monocytopenic within the first 48 h of ventilation. Monocytopenia was also observed in mouse models of hypoxic acute lung injury, in which hypoxemia drove the suppression of type I interferon signaling in the bone marrow. This impaired monopoiesis resulted in reduced accumulation of monocyte-derived macrophages and enhanced neutrophil-mediated inflammation in the lung. Administration of colony-stimulating factor 1 in mice with hypoxic lung injury rescued the monocytopenia, altered the phenotype of circulating monocytes, increased monocyte-derived macrophages in the lung and limited injury. Thus, tissue hypoxia altered the dynamics of the immune response to the detriment of the host and interventions to address the aberrant response offer new therapeutic strategies for ARDS.

Impact of COVID-19 on carers of children with tracheostomies.

OBJECTIVES: To explore the impact of the COVID-19 pandemic on the experiences of caregivers of children with tracheostomies. DESIGN: Qualitative semistructured interviews. SETTING: All participants were currently, or had previously cared for, a tracheostomised child who had attended a tertiary care centre in the North of England. Health professionals were purposively sampled to include accounts from a range of professions from primary, community, secondary and tertiary care. PARTICIPANTS: Carers of children with tracheostomies (n=34), including health professionals (n=17) and parents (n=17). INTERVENTIONS: Interviews were undertaken between July 2020 and February 2021 by telephone or video link. MAIN OUTCOME MEASURE: Qualitative reflexive thematic analysis with QSR NVivo V.12. RESULTS: The pandemic has presented an additional and, for some, substantial challenge when caring for tracheostomised children, but this was not always felt to be the most overriding concern. Interviews demonstrated rapid adaptation, normalisation and varying degrees of stoicism and citizenship around constantly changing pandemic-related requirements, rules and regulations. This paper focuses on four key themes: 'reconceptualising safe care and safe places'; 'disrupted support and isolation'; 'relationships, trust and communication'; and 'coping with uncertainty and shifting boundaries of responsibility'. These are described within the context of the impact on the child, the emotional and physical well-being of carers and the challenges to maintaining the values of family-centred care. CONCLUSIONS: As we move to the next phase of the pandemic, we need to understand the impact on vulnerable groups so that their needs can be prioritised.

Role of immunosuppression in an antibiotic stewardship intervention and its association with clinical outcomes and antibiotic use: protocol for an observational study (RISC-sepsis).

INTRODUCTION: Sepsis is characterised by a dysregulated immune response to infection, with exaggerated pro-inflammatory and anti-inflammatory responses. A predominant immunosuppressive profile affecting both innate and adaptive immune responses is associated with increased hospital-acquired infection and reduced infection-free survival. While hospital-acquired infection leads to additional antibiotic use, the role of the immunosuppressive phenotype in guiding complex decisions, such as those affecting antibiotic stewardship, is uncertain. This study is a mechanistic substudy embedded within a multicentre clinical and cost-effectiveness trial of biomarker-guided antibiotic stewardship. This mechanistic study aims to determine the effect of sepsis-associated immunosuppression on the trial outcome measures. METHODS AND ANALYSIS: RISC-sepsis is a prospective, multicentre, exploratory, observational study embedded within the ADAPT-sepsis trial. A subgroup of 180 participants with antibiotics commenced for suspected sepsis, enrolled in the ADAPT-sepsis trial, will be recruited. Blood samples will be collected on alternate days until day 7. At each time point, blood will be collected for flow cytometric analysis into cell preservation tubes. Immunophenotyping will be performed at a central testing hub by flow cytometry. The primary outcome measures are monocyte human leucocyte antigen-DR; neutrophil CD88; programmed cell death-1 on monocytes, neutrophils and T lymphocytes and the percentage of regulatory T cells. Secondary outcome measures will link to trial outcomes from the ADAPT-sepsis trial including antibiotic days; occurrence of hospital-acquired infection and length of ICU-stay and hospital-stay. ETHICS AND DISSEMINATION: Ethical approval has been granted (IRAS 209815) and RISC-sepsis is registered with the ISRCTN (86837685). Study results will be disseminated by peer-reviewed publications, presentations at scientific meetings and via patient and public participation groups and social media.

Delayed induction of type I and III interferons mediates nasal epithelial cell permissiveness to SARS-CoV-2.

The nasal epithelium is a plausible entry point for SARS-CoV-2, a site of pathogenesis and transmission, and may initiate the host response to SARS-CoV-2. Antiviral interferon (IFN) responses are critical to outcome of SARS-CoV-2. Yet little is known about the interaction between SARS-CoV-2 and innate immunity in this tissue. Here we apply single-cell RNA sequencing and proteomics to a primary cell model of human nasal epithelium differentiated at air-liquid interface. SARS-CoV-2 demonstrates widespread tropism for nasal epithelial cell types. The host response is dominated by type I and III IFNs and interferon-stimulated gene products. This response is notably delayed in onset relative to viral gene expression and compared to other respiratory viruses. Nevertheless, once established, the paracrine IFN response begins to impact on SARS-CoV-2 replication. When provided prior to infection, recombinant IFNß or IFNλ1 induces an efficient antiviral state that potently restricts SARS-CoV-2 viral replication, preserving epithelial barrier integrity. These data imply that the IFN-I/III response to SARS-CoV-2 initiates in the nasal airway and suggest nasal delivery of recombinant IFNs to be a potential chemoprophylactic strategy.